The invention relates to the manufacture of locks of hair from synthetic fibers.
In certain trades such as the manufacture of wigs, dolls or hair dyes, there is often a need for locks of hair. In the case of dyes, for example, locks of hair are used to demonstrate to the clientele in hairdressing salons the different colors or shades which are available to them. Usually, these locks of hair are placed on a display card such as the one shown in FIG. 1. The display card 1 is a board, preferably made of cardboard, perforated with small holes 2 through which are threaded locks of hair 3 mostly made of synthetic fibers (polyamide or nylon, for example), owing to the high cost of real hair.
Since the display cards are designed to be handled frequently, it is necessary for the fibers which make up each lock of hair to be fixed together firmly at either end of the lock of hair.
Some manufacturers use staples, as shown in FIG. 2. However this type of fastening is not very firm and the staples 4 are liable to damage the display card at the place where the holes 2 are made, thus making it impossible to re-use the presentation card for other locks of hair of different shades.
A gas-heated blade has also been used for the manufacture of locks of hair. In this case, the cutting of the long bundles of fibers is carried out at the same time as the welding of these fibers at the cut ends. This technique has the following advantages: (a) two operations i.e., the cutting and the joining together of the fibers at the ends of the locks of hair, are carried out simultaneously; and (b) the join of the fibers, obtained by welding, is a very strong one.
Nevertheless, this technique has major disadvantages: at the time of welding, the material of which the fibers are composed is brought to a high temperature for a time sufficiently long to allow this material to flow. The welding is not perfect: it is not homogenous, extends over a relatively long length at each end of the lock of hair, and contains burrs which are liable to spoil the presentation card when the locks of hair are fitted. Moreover, this process is not very economical and the formation of smoke cannot be avoided.